Various types of color display technologies are known in the art. For example, there are CRT display systems, LCD systems, and projection display systems. In front projection displays, the projected images are viewed from a reflective viewing screen. In rear projection displays, the projected images are viewed through a transmissive viewing screen.
To produce color images, existing display devices use three primary colors, typically, red green and blue, collectively referred to as RGB. In simultaneous projection display systems, the three primary color components of the image are modulated and displayed simultaneously using one or more SLMs.
FIG. 1 schematically illustrates an optical configuration of a RGB display device 100 implementing three transmissive Liquid Crystal Display (LCD) panels to produce a color image. The device includes an illumination unit 101 and a dichroic mirror 102 to reflect the part of the light produced by unit 101 having a blue spectrum, and to transmit the other parts of the light. The reflected blue light is further reflected by a mirror 104 and passes through a transmissive LCD panel 107 according to a pattern corresponding to a blue component of the image. A dichroic mirror 103 reflects the part of the light transmitted by mirror 102 having a green spectrum and transmits the other parts of the light. The reflected green light passes through a LCD panel 108 according to a pattern corresponding to a green component of the image. The part of the light transmitted by mirror 103, is further reflected by mirrors 105 and 106 and passes through a LCD panel 109 according to a pattern corresponding to a red component of the image. An X-cube 110 combines the light transmitted by panels 107, 108 and 109 to form a combined light beam. The combined light beam is projected on a screen by a projection lens 111. The device may include narrow band filters in order to increase saturation of the colors. However, the use of the narrow band color filters will provide a decreased brightness of the display.